No BMS anywhere. Trust me, I've worked with BMS units from a few different suppliers (CleanPowerAuto for one) and they are designed for full-fledged EV's, not golf carts. For the comparatively low Amp draw of golf carts you don't need a BMS - All they really do is cut into the throttle when you're at low voltage and tell the charger to shut off during charging at high voltage... We can do that with a little common sense and a quality charger.

You're correct in assuming that a new charger is best. We've charged the lithium batts up just fine with the PowerDrive charger on the Precedent, but it's a pain because you have to babysit it a little, and the charging algorithms aren't optimized for lithium so it still takes about 5 hours for a charge (from 70% DoD.) Still, that's not bad, and it saves you the initial cost of the charger if you're ok with monitoring the charging yourself. The thing is, a smart charger that's lithium-specific will complete a full charge in 2-3 hours, so you'll make back the cost of the charger on energy savings in 3 or 4 years.
As for the price, we offer the full package -which includes a battery indicator and charger - for $1736. That's our 12V40Ah package. If you want a more serious range increase, you can go with 60Ah or 90Ah packages, which are $2312 and $3176.
Yes, the sticker price is considerably higher than the best lead-acid batteries. But think about it this way: the 90Ah batteries (cost $3176) go 3x as far per charge and last 4x as many cycles. So you'd have to buy 12 sets (4 x 3) of T-1275's for every 1 Lithium set to get equal performance (and that's only a dream anyway because you could never fit 3 sets of lead-acid batteries in a cart to get that kind of range.) 12 Trojan T-1275's are going to cost you at least $2400 even if you get them cheap, compared to $650 for 1 Lithium battery. They're WAY CHEAPER per cycle.
And that's just looking at range and cycles. They're also much lighter and smaller, have a crazy-low self-discharge rate (2-3% monthly), aren't influenced by temperature like lead-acid, and don't require any maintenance (no corrosion!)
Sorry that was so many words... I just can't shut up about these things

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Sonic, to get more specifically at what you were asking...
The 12v block batteries have an ultra simple BMS inside which keeps them happy. As far as overcharging is concerned, the charger is what takes care of that. Or, if you don't want to buy a new charger, you can just keep your multimeter handy during charging and do it yourself. But the lead-acid algorithms of your OEM charger won't make your lithium batteries as happy.
The reason I stated that it charges quicker is because the chemistry of an LiFePO4 battery is way more efficient than lead-acid chemistry. So yes, the amount of potential energy you are returning into the battery by charging is similar, but the process of returning it is a chemical reaction with significantly less wasted energy (like heat) and no hydrogen gas produced (which is also wasted energy), hence less energy used.

Oh, and the 3C rating is for both charging and discharging. (the 10C impulse rating is for 10 seconds).

No BMS anywhere. Trust me, I've worked with BMS units from a few different suppliers (CleanPowerAuto for one) and they are designed for full-fledged EV's, not golf carts. For the comparatively low Amp draw of golf carts you don't need a BMS - All they really do is cut into the throttle when you're at low voltage and tell the charger to shut off during charging at high voltage... We can do that with a little common sense and a quality charger.

You're correct in assuming that a new charger is best. We've charged the lithium batts up just fine with the PowerDrive charger on the Precedent, but it's a pain because you have to babysit it a little, and the charging algorithms aren't optimized for lithium so it still takes about 5 hours for a charge (from 70% DoD.) Still, that's not bad, and it saves you the initial cost of the charger if you're ok with monitoring the charging yourself. The thing is, a smart charger that's lithium-specific will complete a full charge in 2-3 hours, so you'll make back the cost of the charger on energy savings in 3 or 4 years.
As for the price, we offer the full package -which includes a battery indicator and charger - for $1736. That's our 12V40Ah package. If you want a more serious range increase, you can go with 60Ah or 90Ah packages, which are $2312 and $3176.
Yes, the sticker price is considerably higher than the best lead-acid batteries. But think about it this way: the 90Ah batteries (cost $3176) go 3x as far per charge and last 4x as many cycles. So you'd have to buy 12 sets (4 x 3) of T-1275's for every 1 Lithium set to get equal performance (and that's only a dream anyway because you could never fit 3 sets of lead-acid batteries in a cart to get that kind of range.) 12 Trojan T-1275's are going to cost you at least $2400 even if you get them cheap, compared to $650 for 1 Lithium battery. They're WAY CHEAPER per cycle.
And that's just looking at range and cycles. They're also much lighter and smaller, have a crazy-low self-discharge rate (2-3% monthly), aren't influenced by temperature like lead-acid, and don't require any maintenance (no corrosion!)
Sorry that was so many words... I just can't shut up about these things

The reason I stated that it charges quicker is because the chemistry of an LiFePO4 battery is way more efficient than lead-acid chemistry. So yes, the amount of potential energy you are returning into the battery by charging is similar, but the process of returning it is a chemical reaction with significantly less wasted energy (like heat) and no hydrogen gas produced (which is also wasted energy), hence less energy used.

ok, i see what you're saying... watthours are not being wasted by the conditioning phase. this is a function of the battery chemistry coupled with a balancing charge system, not truly a function of time. lead acid batteries would require significantly less time in the conditioning phase if charged with a similar balancing charger.

Quote:

the 90Ah batteries (cost $3176) go 3x as far per charge

how does your 90Ah battery go 3x as far as trojan's 150Ah battery?

Quote:

and last 4x as many cycles.

a 40Ah battery with a C rating of 3 is good for only 120amps. consistently discharging a battery at or near its full C rating will significantly decrease its cycle life. what is the cycle life of these cells if discharged at full C? 100? 200 cycles? i have a feeling its nowhere 3000!

don't get me wrong, im a fan of lifepo4, but your claims are coming across as nothing more than qualitative technobabble. let us see some real quantitative specifications!
-sj

Sonicj, I can totally respect and appreciate some challenges from people, especially those who've been around carts for a while.
First off, I've only been working on our cart for about 4 months. I certainly don't claim to know everything, but I've learned a lot - some on my own, and a lot from good folks on this forum.
One thing I've learned is that the lithium batteries I put in to replace the Trojan T-1275's that came with the cart took me a LOT further. Before I took the old ones out, I did a range test on a 1/4-mile loop in a flat parking lot. My run time was about 70 minutes before I got noticeably slower. The new batteries were 60Ah LiFePO4 batteries, and ran for 2 1/2 hours straight when I went out for my first range test with them. (This was in a public park with elevation changes.) I don't know how Amp Hour Ratings get assigned to Wet cells and to Lithium batteries. But I personally experienced that the 60Ah lithium cells doubled the range of the 120Ah/150Ah Trojan T-1275's. By my estimation, those batteries perform to the equivalent of 30Ah lithium batteries, so 40Ah lithiums should take you about 33% further than T-1275's. I haven't tested any T-105's or T-605's or anything else, but I gather real quick that the rest of the Sparky owners here already have more than enough data for those to help me out.
I also put a set of 60's in a Yamaha YDR (2007 i think?) which we have loaned to us by a curious dealer out. Same results there. The cart gives us well over 150 minutes of straight pedal time. We suspect that if it were used in a more realistic stop and go, it would give you even more range because, just like other batteries, the voltage likes to rebound on its own a little bit when you let it sit.
We're getting some 40Ah batteries in the next month so that I can confirm the range projections.

What is a BMS?
Where are these batteries manufactured?
Can they be shipped by conventional means?
What is the warranty?
Is there a dealer network?
Does anyone other than yourself have this product in service?

fair enough! thats actually a pretty good example of real world testing imo.

unfortunately, the lead acid manufacturers are often vague in their specifications and data collection techniques. this makes comparing apples to apples difficult if not impossible. the problem is the Peukert effect; in lead acid batteries as amp draw increases, capacity decreases. therefore, publishing a 20 hour rate has little relevance to those who will be discharging the battery at a 100 min rate.

if you look at a discharge graph of a lead acid battery, you'll notice its pretty linear.

in contrast, the lifepo4 in the 2nd graph has a very sharp curve near the end of the discharge test.

so what does all this mumbo jumbo mean to average golf cart pilot? assuming similar under load capacities, with the lifepo4 pack, you'll have that fresh off the charger speed and punch pretty much through the entire discharge cycle, while your buddy with lead acid will be slow and sluggish long before his entire pack is depleted. the down side to this is that the lifepo4 can leave you stranded if you aren't monitoring Ah consumed. lead acid will give you a clue as to when its time to head home to recharge.

another thing to note is the green curve in the 2nd graph. this one is a NiMh battery which is actually rated at more capacity than the lifepo4, but when tested under load falls far short of its stated capacity. in this example, lifepo4 shows more usable mAh over the NiMh pack. this is similar to the Peukert effect and what you may have experienced in your tests, but has more to do with voltage drop under load. unfortunately, i don't have a side-by-side test with a lead acid of similar capacity to add to the graph...

hope this sheds some insight on your test results! im looking forward to more real world comparisons with your company's products.
-sj

What is a BMS?
Where are these batteries manufactured?
Can they be shipped by conventional means?
What is the warranty?
Is there a dealer network?
Does anyone other than yourself have this product in service?

A BMS is a circuitboard which is wired to each individual cell in a lithium system. Simple ones cost about $100-$300, but fancy ones can be $3,000 or more.

These particular batteries are made in China. As someone else already noted, nearly all lithium batteries are coming from China, Japan, or Korea right now. If you want US made lithium batteries, A123Systems is about your only option. They cost 2-3x as much as batts from China.

Sure, they can be shipped by conventional means - (if breaking the law is your kind of thing...) LOTS of shippers of these batteries send them out illegally in non-UN specification packaging (non Hazmat.) I spent about 2 months certifying and getting our ducks in a row so that these batteries are shipped according to DOT regulations (and IATA when necessary.)

The warranty is 2 years. There's no reason to think they won't go 10+ years, but there's too many people out there who will wreck them out of stupidity if we give them enough warranty time.

We're working on building a dealer network. I can't talk details on the forum, but anyone can PM me if interested in more information.

As far as others offering this, I'm only aware of one other in the US - just google '12v lithium golf cart battery' Lots of Chinese companies sell them, but they're all pretty pricey.

i have tried to follow this as best i could and to me some makes perfect sense some dosn,t but if you want a real world opinion......good luck in getting people to spend that kind of money on batteries.....there may be a golfcart market but its gonna be tiny and i,ll say it now my money says it never flies.....not because of the product just plain and simple cost......you can,t get people now to spend 1000 on a set of good batteries how are you gonna get them to spend 2 grand........sorry i just don,t see thats going to happen......oh i,m sure there are a few people with enough money to put it out but for most of us 95% of us thats way out of price range .......cripes they cost more than 1/2 the carts out there riding around.......again please its not the product al all if i had the dough i,d love to try a set........its pure cost...................................